Fuel injected internal combustion engines have in recent years been employed by automotive manufacturers as a more fuel efficient alternative to conventional carbureted engines. Moreover, fuel injected internal combustion engines provide a more accurate means (as compared to carbureted engines) to control a variety of engine operating parameters via an on-board electronic control unit (ECU).
Fuel is typically supplied to the injectors by means of one or more rigid conduits (usually referred to as "fuel rails" in art parlance). The fuel rails are thus adapted to receiving the injectors at spaced-apart locations along the fuel rail so as to be in alignment with respective positions of the intake ports of an internal combustion engine. In such a manner, fuel from the vehicle's fuel system may be supplied to the individual injectors via the fuel rail.
During production of fuel injected internal combustion engines, the fuel rail will usually have the injectors dependently attached thereto in some fashion (usually via a clip). This fuel rail/injector subassembly may then be mated with an engine block during assembly line production so that the injectors are positioned within respective intake ports of the engine.
Mating of the fuel rail/injector subassembly usually presents little problems during production of in-line configured engines (e.g., a four cylinder engine in which all of the cylinders are oriented "in-line" relative to the engine block). However, potential problems relating to angular mismatch as between the injectors of the fuel rail/injector subassembly and the intake ports of the engine block in which the injectors are to be seated may occur with V-configured engines (e.g., six or eight cylinder engines in which one bank of cylinders is situated laterally of the other cylinder bank, with the respective cylinder banks being oriented in a V-shape as viewed from the end of the engine block). For these reasons, it would be very desirable if the fuel rail included the means by which any angular mismatch between the fuel rail/injector subassembly and the intake ports of the engine block could be corrected on line during manufacturing.
As indicated briefly above, fuel rails must ultimately be connected to the vehicle's fuel system which usually entails connecting an inlet and an outlet of the fuel rail to "quick connectors" of conduits (typically flexible conduits) associated with the supply and return sides, respectively, of the vehicle's fuel system. Hence, during production, it would also be very desirable if the inlet and outlet of the fuel rail were each closely located relative to one another so that the interconnection with the vehicle's fuel system may be more efficiently accomplished by an assembly line worker.
It is towards achieving such desired attributes of automotiVe fuel rails that the present invention is specifically directed.
According to one aspect of the present invention, a novel fuel rail is provided which includes the means by which angular mismatch between the fuel rail/injector subassembly is capable of being corrected on line during manufacture of the engine. At least one end of the fuel rail defines a recess in which an end of a rigid fuel conduit is accepted. The fuel conduit is itself provided with an annular flange which is retained in the recess of the fuel rail by means of a fixed-position, arcuately shaped retainer flange. The end of the retainer flange thus bears against the annular flange of the fuel conduit so as to retain the latter within the recess of the fuel rail, while yet also allowing relative rotational movements between the fuel rail and the fuel conduit. This relative rotational movement may then be used during manufacture so as to correct any angular mismatch which may be present between the fuel rail/injector subassembly and the engine block.
Inlet and outlet nipples may also be provided closely adjacent one another according to another aspect of this invention. That is, the present invention also contemplates a fuel rail comprised of a pair of substantially concentrically disposed conduits which define therebetween an annular space through which fuel may flow. Means may be provided at a terminal end of the inner conduit so as to positionally concentrically retain it within the outer conduit, and to establish fluid communication between the inner conduit and the annular passageway. In such a manner, the fuel rails of this invention may establish countercurrent flow of fuel therewithin.
These, as well as other aspects and advantages of this invention will become more clear after careful consideration is given to the detailed description of the preferred exemplary embodiments which follow.